React.js文件上传UI拖放不起作用

Question

我正在尝试为我的 react.js 应用程序编写文件上传。但是，我无法让拖放区正常工作。 即使我停止传播并阻止拖放事件的默认值，它仍然无法按预期工作。浏览器仍然打开我的文件。

export default function DraggableUploader() {

    const fileInput = useRef(null)
    const [loadedFile, setLoadedFile] = useState(null)
    const [isLoading, setIsLoading] = useState(false)

    const handleDragEnter = e => {
        e.preventDefault();
        e.stopPropagation();
      };
    const handleDragLeave = e => {
        e.preventDefault();
        e.stopPropagation();
    };
    const handleDragOver = e => {
        e.preventDefault();
        e.stopPropagation();
    };
    const handleDrop = e => {
        e.preventDefault();
        e.stopPropagation();

    };


    function handleSubmit(e) {
        e.preventDefault()
        console.log(`current file`, loadedFile.name)



    }

    return (
        <div className="dropzone">
            <div className="sub-header">Drag your audio file here:</div>
            <div className="draggable-container">
                <input 
                    type="file" 
                    className="file-browser-input"
                    name="file-browser-input"
                    style={{display: "none"}}
                    ref={fileInput} 
                    onDrop={e => handleDrop(e)}
                    onDragOver={e => handleDragOver(e)}
                    onDragEnter={e => handleDragEnter(e)}
                    onDragLeave={e => handleDragLeave(e)}
                    onChange={handleInputChange}  
                />


                <div className="file-browser-container">
                    <Button variant="outline-primary" onClick={handleInputClick}>Browse</Button>

                </div>

            </div>
            <Button variant="primary" onClick={handleSubmit}>Submit</Button>
        </div>
    )
}

Answer 1

显然我没有 useEffect 来添加事件侦听器。如果您添加以下代码，一切都按预期工作：

useEffect(() => {
        let div = dropRef.current;
        div.addEventListener('dragenter', handleDragEnter);
        div.addEventListener('dragleave', handleDragLeave);
        div.addEventListener('dragover', handleDragOver);
        div.addEventListener('drop', handleDrop);
        return function cleanup() {
          div.removeEventListener('dragenter', handleDragEnter);
          div.removeEventListener('dragleave', handleDragLeave);
          div.removeEventListener('dragover', handleDragOver);
          div.removeEventListener('drop', handleDrop);
        };
      });

Answer 2

如果您使用箭头函数，则不需要附加事件侦听器。使用下面的代码所有事件都可以工作，我在上面的代码中看到的唯一问题是将隐藏输入上的事件附加到最外层的 div 上，它将起作用。祝你好运！

export default function App() {

  const handleDragEnter = e => {
    e.preventDefault();
    console.log("drag enter");
  };

  const handleDragLeave = e => {
    e.preventDefault();
    console.log("drag leave");
  };

  const handleDragOver = e => {
    e.preventDefault();
    console.log("drag over");
  };

  const handleDrop = e => {
    e.preventDefault();
    console.log("drag drop");
  };

  const handleInputChange = () => {};

  return (
    <div
      className="dropzone"
      onDrop={e => handleDrop(e)}
      onDragOver={e => handleDragOver(e)}
      onDragEnter={e => handleDragEnter(e)}
      onDragLeave={e => handleDragLeave(e)}
      onChange={handleInputChange}
    >
      <div className="sub-header">Drag your audio file here:</div>
      <div className="draggable-container">
        <input
          type="file"
          className="file-browser-input"
          name="file-browser-input"
          style={{ display: "none" }}
        />
      </div>
    </div>
  );
}